Outboard drive unit for watercraft



Jim, 9 1970 c. F. ALEXANDER, m 3,487,80

OUTBOARD DRIVE UNIT FOR WATERCRAFT 2 Sheets-Sheet 1 Filed Jan. 15, 1968 3mm W70 g. F. ALEXANDER, m

OUTBQARD DRIVE UNIT FOR WATERCRAFT 2 Sheets-Sheet Filed Jan. 15, 1968 R MN): EAI/ H r Km 5/ m M f United States Patent US. Cl. 11517 8 Claims ABSTRACT OF THE DISCLGSURE A generally horizontal propeller shaft is rotatably disposed in the lower unit of an outboard drive and projects from such unit to carry a propeller. A generally vertical drive shaft is rotatably disposed in the drive shaft housing of the outboard drive and extends downwardly into the lower unit with the lower end of the drive shaft spaced above the propeller shaft. A plurality of generally vertical driven shafts are disposed in the lower unit and are drivingly connected to the propeller shaft. Reversing gear means connect the drive shaft to the driven shafts and provide for propeller rotation selectively in the forward and reverse directions. The invention further contemplates a transmission arrangement wherein changes in gear ratio can be made to suit the type of operation contemplated for the drive unit.

This invention relates to an outboard drive unit for watercraft and more particularly to a multiple shaft transmission for such a unit.

The invention contemplates a multiple shaft transmission arrangement wherein the torque load for driving the propeller shaft is divided among a plurality of shafts in the drag imposing lower unit. As a consequence of this division of torque load, smaller transmission components may be used for driving the propeller shaft and a correspondingly smaller propeller shaft housing is required providing a more eflicient lower unit having a lesser drag imposing frontal area in operation. In keeping with the general objective of providing a more efiicient lower unit, the reversing gear means have been removed from their conventional location in the propeller shaft housing and are disposed in the enlarged upper portion of the lower unit above water level. The invention further contemplates a transmission arrangement wherein changes in gear ratio can be made with relative ease to suit the type of operation contemplated for the drive unit.

Generally according to the invention, a generally horizontal propeller shaft is rotatably disposed in the lower unit of an outboard drive and projects from such unit to carry a propeller. A generally vertical drive shaft is rotatably disposed in the drive shaft housing of the outboard drive and extends downwardly into the lower unit with the lower end of the drive shaft spaced above the propeller shaft. A plurality of generally vertical driven shafts are disposed in the lower unit and are drivingly connected to the propeller shaft; and reversing gear means connect the drive shaft to the driven shafts and provide for propeller rotation selectively in the forward and reverse directions.

The accompanying drawings illustrate the best mode presently contemplated for carrying out the invention.

In the drawings:

FIGURE 1 is a partial elevational view of the drive unit of this invention with parts broken away and sectioned;

FIGURE 2 is a sectional view taken generally on line 22 of FIG. 1;

FIG. 3 is a sectional view taken generally on line 3-3 of FIG. 1;

FIG. 4 is a sectional view taken generally on line 4-4 of FIG. 1; and

FIG. 5 is a fragmentary view generally similar to a corresponding portion of FIG. 1 and shows an alternate mounting for the bevel gears on the propeller shaft to provide for propeller rotation in the: direction opposite to that of FIG. 1.

Referring to the drawings, an outboard drive unit such as an outboard motor 1 includes the usual transom bracket 2 for mounting the motor onto the transom 3 of the watercraft 4. A swivel bracket 5 is interposed between the transom bracket 2 and the power unit 6 and provides for tilt movement of the power unit in a generally vertical plane about an axis defined by the generally horizontal tilt pin 7 carried by the transom bracket. Swivel bracket 5 further includes a hollow, generally upright steering post 8 providing for movement of the power unit 6 in a generally horizontal plane for steering.

The power unit 6 includes a drive shaft housing 9 supporting the engine 10 at the upper end thereof enclosed by the cowl 11. A lower unit 12 is carried at the lower end of power unit 6 and contains a generally hori zontal propeller shaft 13 which projects rearwardly from the unit and carries the propeller 14 thereon beneath the generally horizontal anti-cavitation plate 15. The lower unit 12 is joined to the drive shaft housing 9 along the generally horizontal parting line 16 by a plurality of stud bolts, only one of which is shown.

The power transmission means connecting the engine 10 to the propeller shaft 13 includes the generally vertical drive shaft 17 which is drivingly connected to the engine crankshaft 18 and extends downwardly from the engine through housing 9 and into the gear case 19 provided in the upper portion of lower unit 12. Adjacent to the lower end of drive shaft 17 a spur gear 20' is mounted to be freely rotatable thereon and is disposed in meshing engagement with the spur gear 21 keyed on the vertically disposed driven shaft 22 by a suitable spline connection.

The driven shaft 22 extends vertically downward within the lower unit 12 and terminates within the horizontal bore 23 in the propeller shaft housing 24. A spur gear 25 is splined on the upper end of driven shaft 22 for rotation therewith and is spaced beneath the gear 21 as provided by the spacer sleeve element 26. The gear 25 is disposed in meshing engagement with the spur gear 27 which is suitably splined on the intermediate parallel driven shaft 28, which like driven shaft 22 extends downwardly in the lower unit 12 and terminates in the propeller shaft bore 23. The spur gear 27 in turn meshes with the spur gear 29 suitably splined on the forwardly disposed, parallel driven shaft 30 which is axially spaced and aligned beneath the drive shaft 17. The driven shaft 30, like driven shafts '22 and 28, extends downwardly in the lower unit 12 and terminates in the bore 23 for the propeller shaft 13. The spur gears 25, 27 and 29 are disposed in the generally out-of-water portion of lower unit 12 above the anti-cavitation plate 15 and comprise timing gears having like diameter and number of teeth to synchronize the rotation of the driven shafts 22, 28 and 30 to provide that the like bevel pinion gears 31 carried on the lower ends of the respective driven shafts in propeller shaft bore 23 will all rotate at the same speed.

The power transmission arrangement provides that of the total torque load exerted by the engine 10 on drive shaft 17, each of the shafts 22, 28 and 30 carries generally one-third of the load to the propeller shaft 13. The shafts 22, 28 and 30 taper upwardly to a reduced diameter to provide a section of lesser torsional stiffness so that the driven shafts can deflect torsionally under load to substantially equalize tooth pressures on the bevel gear connections to the propeller shaft 13.

The propeller shaft 13 extends horizontally beneath the driven shafts 22, 28 and 30 and is rotatably supported in bore 23 by a pair of spaced, opposed tapered roller bearings 32 and 33. As generally shown in FIG. 1, a bevel gear 34 is suitably keyed onto the propeller shaft 13 and is disposed in abutting relation with bearing 32 and in meshing engagement with pinion gear 31 on driven shaft 22. Bevel gears 35 and 36 are further keyed onto the propeller shaft 13 in meshing engagement with the corresponding pinion gears 31 on shafts 28 and 30 respectively and may be disposed on a common hub as shown. Proper meshing engagement of the gears 34, 35 and 36 with the corresponding pinion gears 31 is assured by the respective axially extending spacer sleeves 37 and 38 disposed on shaft 13 between gears 34 and 35 and between the gear 36 and the bearing 33. The inner race of bearing 33, spacer sleeve 38, bevel gears 35 and 36, spacer sleeve 37, bevel gear 34 and the inner race of bearing 32 are drawn tightly together on propeller shaft 13 between the rearwardly disposed annular spacer element 39 abutting on the annular, forwardly facing shoulder 40 and the nut 41 on the forward end of the propeller shaft to form a unitary assembly 42 for rotatably carrying the propeller 14. The assembly 42 is secured against movement axially within the bore .23 by engagement of the outer race of bearing 32 against the forwardly facing, inwardly stepped shoulder 43 in the bore rearwardly of the assembly, and by the forwardly disposed annular element 44 which is threadedly engaged within the bore and abuts against the outer race of bearing 33.

A cylindrical seal support member 45 is disposed in the bore 23 ahead of the assembly 42 and is stepped forwardly thereof to accommodate an annular sealing member 46. The member 45 is provided with a plurality of locking projections 47 which extend rearwardly and engage within corresponding recesses 48 in the threaded element 44 to insure the integrity of the threaded connection of element 44 and the security of the assembly 42. Forwardly of member 45 a washer 49 confines the sealing member 46 and bears forwardly against a snap ring 50 disposed within an appropriate recess in the wall of bore 23. The nut 51 is threadedly engaged on the forwardly extending cylindrical projection 52 on member 45 and bears on the snap ring 50 to draw the sealing member and washer 49 up tightly to properly seat the sealing member 46 against the wall of bore 23.

The bore 23 is closed forwardly by a hollow, generally conical nose member 53 which engages into the bore opening and is secured in place by a bolt '54. The bolt 54 threadedly engages into a cylindrical recess 55 in projection 52 of member 45 and is provided with a conical head 56 which forms an apex on nose member 53 to provide a torpedo or bullet shaped propeller shaft housing 24 on lower unit 12.

The marine drive unit further includes reversing gear means in the gear case 19 including a shiftable coupling or clutch element 57 disposed on drive shaft 17 beneath the spur gear 20. Shaft 17 is provided with spline grooves 58 beneath gear 20 which are complemented by the internal spline groove construction of clutch element 57 providing for rotation of the clutch element with the drive shaft while permitting relative axial movement therebetween. The clutch element 57 as shown in FIG. 1, is disposed in the neutral position intermediate the spur gear 20 on drive shaft 17 and the spur gear 29 on driven shaft 30.

For forward drive operation the clutch element 57 is moved axially in the direction of spur gear 20 to place the radially extending clutch teeth 59 on the clutch element into driving engagement with the corresponding clutch teeth 60 on gear 20. With the gear 20 drivingly interlocked to the drive shaft 17 through clutch element 57, the spur gear 21 and its driven shaft 22 and spur gear 25 are correspondingly set in motion to drive the shafts 28 and 30, through spur gears 27 and 29. The shafts 22, 28 and 30 and their respective pinion gears 31 in turn drive the propeller shaft 13 and propeller 14 correspondingly through bevel gears 34, 35 and 36.

For reverse drive operation the clutch element 57 is moved axially in the direction of spur gear 29 and the clutch teeth 61 on the clutch element drivingly engage the corresponding clutch teeth 62 on gear 29. With the gear 29 and its driven shaft 30 drivingly interlocked to the drive shaft 17 through the clutch element 57, the spur gears 27 and 25 and their related driven shafts 28 and 22 are correspondingly set in motion to drive the propeller shaft 13 and propeller 14 in the direction for reverse operation through the several bevel gear sets. During reverse drive operation, the spur gear 21 on shaft 22 and gear 20 are simply permitted to idle.

Axial movement or shifting of clutch element 57 between its extreme positions for forward and reverse drive respectively is accomplished with a rotatably supported shift shaft 63 which extends from gear case 19 upwardly through the hollow steering post 8 and into the cowl enclosure 11. A lever 64 is secured to the upper end of shaft 63 and is movable angularly by means of a suitable remote control unit, not shown, to rotate the shaft. A cam element 65 is carried at the lower end of shaft 63 and is provided with opposed spiral cam grooves or ramps 66 which are engaged by corresponding follower pins 67 on the adjacent end of the shifting lever 68. The lever 68 is pivotally supported intermediate its length by a projection 69 and the end of the lever oppositely disposed from cam element 65 is adapted to carry pin projections 70 extending radially from a shifting collar 71 which rides within the peripheral recess 72 of clutch element 57 to accommodate rotation of the clutch element with drive shaft 17 relative to the collar and its actuating lever.

As generally shown in FIG. 1, the clutch element 57 is disposed in the engine idling or neutral position intermediate the gears 20 and 29 when the follower pin 67 is disposed in a correspondingly intermediate position of the spiral cam groove 66. With selective rotation of shaft 63 and cam element 65 in either direction from the neutral position, the follower pin 67 moves relative to the cam groove 66 to pivot the shifting lever 68 correspondingly and thereby move the shifting collar 71 along with clutch element 57 into the forward and reverse drive positions respectively. Shift shaft 63 is rotated in the opposite di rection to return the clutch element 57 to the neutral position and a detent spring means 73 may be adapted to give a feel indication for that position.

Water for engine cooling is circulated through the engine 10 by the pump 74 disposed in the drive shaft housing 9 and driven by the drive shaft 17. So situated, the pump 74 remains effective to circulate cooling water even while the engine 10 and shaft 17 are idling. The water for cooling enters the cooling system through a plurality of suitable inlet openings 75 provided in the conical nose member 53 on lower unit 12. At least some of the inlet openings 75 are disposed in member 53 beneath the center line of the propeller shaft 13 to assure an adequate supply of coolant for engine 10 even when the motor 1 is being operated with the propeller 14 being driven under surfacing propeller conditions with only the lower half of the propeller in the water. From the conical nose member 53 the coolant water reaches the pump 74 through a circuitous passage 76 and the passage 77 conducts the water from the pump to the engine 10.

For the outboard motor 1, it is a relatively simple matter to effect a change in gear ratio between the drive shaft 17 and propeller shaft 13. With disassembly of lower unit 12 from the drive shaft housing 9 along the parting line 16, and removal of the gear case cover assembly 78 from the lower unit along the parting line 79, the speed ratio determining gears 20 and 21 are exposed. For a change in gear ratio only gears 20 and 21 need be replaced with gears providing the desired ratio, there being no need for disassembly of the relatively delicate set-up of the multiple driven shafts 22, 28 and 30 and/or the right angle bevel gearing connecting the driven shafts and the propeller shaft 13 in the bore 23 of housing 24. The cam 65 at the lower end of shift shaft 63 is provided with a recess 80 in radial alignment with the gear teeth on gear 20 to accommodate without interference certain larger gears in replacement of gear 20 providing for a different gear ratio. The arrangement permits selection from a relatively wide range of possible gear ratios.

If counterrotation of propeller shaft 13 is desired from the arrangement shown in FIG. 1, it becomes necessary only to change the location of the bevel gears 34, 35 and 36 on the propeller shaft. Such a change is effected by a mere rearrangement of existing parts on shaft 13 with no additional parts being necessary. As will be gleaned from a comparison of FIGS. 1 and 5, counterrotation of bevel gear 34 is effected by a reinstallation of that gear as gear 81 adjacent to the forward bearing 33 and in meshing engagement with pinion gear 31 on shaft 30. Counterrotation of bevel gears 35 and 36, which may be on a common hub, will be effected by a reinstallation of those geafs as gears 82 and 83 respectively disposed in meshing engagement with the pinions 31 of driven shafts 22 and 28 respectively. To accommodate the bevel gears 34, 35 and 36, reversibly reinstalled as gears 81, 82 and 83 with respect to the pinion gears 31 for counterrotation of shaft 13 as shown in FIG. 5, the spacer sleeves 37 and 38 also must be rearranged. From a further comparison of FIGS. 1 and 5, it will be seen that the shorter sleeve 38 is reinstalled as sleeve 84 between the rearwardly disposed roller bearing 32 and the adjacent bevel gear 83. The longer spacer sleeve 37 is reinstalled as sleeve 85 between the bevel gears 81 and 82. No other change is required to provide for counterrotation of shaft 13 over the transmission as shown in FIG. 1 to drive the propeller 86 having pitch of opposite hand from the propeller 14 of FIG. 1.

The lower unit construction of this invention including the multiple shaft transmission together with the fixedly disposed propeller shaft gearing provides a more eflicient lower unit having a substantially decreased frontal area moving through the water in operation. Because changes in gear ratio are effected in the out-of-water portion of the lower unit above the anti-cavitation plate where frontal area is not critical, a wider range of possible gear ratios can be accommodated to increase the versatility of the drive unit.

Various modes of carrying out the invention are contemplated as being within the scope of the following claims particularly pointing out and distinctly claiming the subject matter which is regarded as the invention.

I claim:

1. In an outboard drive having a drive shaft housing and a lower unit carried by said drive shaft housing, said lower unit having a propeller shaft housing and an anticavitation plate spaced above the propeller shaft housing, a generally horizontal propeller shaft rotatably disposed in the propeller shaft housing and projecting therefrom to carry a propeller, a generally vertical drive shaft rotatably disposed in said drive shaft housing and extending downwardly into the portion of the lower unit above the anticavitation plate, a plurality of generally vertical driven shafts extending between the portion of the lower unit above the anti-cavitation plate and the propeller shaft housing with one of said driven shafts being axially aligned with the drive shaft, bevel gear means in said propeller shaft housing and drivingly connecting the driven shafts to the propeller shaft, a pair of meshingly engaged speed ratio determining gears in the portion of the lower unit above the anticavitation plate with one of said speed ratio determining gears disposed on said drive shaft and being rotatable relative thereto, a timing gear secured on each driven shaft in the portion of the lower unit above the anti-cavitation plate, said timing gears having like diameter and number of teeth and being meshingly eugaged to synchronize rotation of the driven shafts, said speed ratio determining gears being drivingly connected to said timing gears and the speed ratio determining gear on said drive shaft comprising a forward drive gear, the timing gear on said driven shaft axially aligned with the drive shaft comprising a reverse drive gear, and coupling means carried by the drive shaft between the forward drive gear and the reverse drive gear, said coupling means having a neutral position intermediate said forward and reverse drive gears and being axially movable relative to the drive shaft to selectively engage the forward and reverse drive gears to couple the corresponding gear to the drive shaft and effect corresponding propeller rotation.

2. The invention as set forth in claim 1 wherein the second of said speed ratio determining gears is secured on one of the driven shafts.

3. The invention as set forth in claim 1 wherein the outboard drive includes an engine mounted on the upper end of the drive shaft housing and the generally vertical drive shaft is drivingly connected to the engine.

4. In an outboard drive having a drive shaft housing and a lower unit carried by said housing, said lower unit having a propeller shaft housing and a gear case spaced above said propeller shaft housing, a generally horizontal propeller shaft rotatably disposed in the propeller shaft housing and projecting therefrom to carry a propeller, a generally vertical drive shaft rotatably disposed in said drive shaft housing and extending downwardly into the gear case, a plurality of generally vertical driven shafts extending between the gear case and the propeller shaft housing, bevel gear means in said propeller shaft housing drivingly connecting the driven shafts to the propeller shaft and comprising a bevel pinion gear carried on each of said driven shafts and a corresponding bevel gear carried on said propeller shaft in meshing engagement with the respective pinion gears to provide for rotation of a propeller, said bevel gears on said propeller shaft being adapted for reverse assembly with respect to the bevel pinion gears to provide for counterrotation of the propeller shaft to drive a propeller having pitch of opposite hand, and reversing gear means in said gear case and connecting the drive shaft to the driven shafts to provide for propeller rotation selectively in the forward and reverse directions.

5. In an outboard drive having a drive shaft housing and a lower unit carried by said housing, said lower unit having a propeller shaft housing and a gear case spaced above said propeller shaft housing, a generally horizontal propeller shaft rotatably disposed in the propeller shaft housing and projecting therefrom to carry a propeller, a generally vertical drive shaft rotatably disposed in said drive shaft housing and extending downwardly into the gear case, a plurality of generally vertical driven shafts extending between the gear case and the propeller shaft housing and being drivingly connected to the propeller shaft, and reversing gear means in said gear case and connecting the drive shaft to the driven shafts to provide for propeller rotation selectively in the forward and reverse directions, the reversing gear means includes a forward drive gear and said forward drive gear is meshingly engaged with a gear carried on one of said driven shafts, said forward drive gear and driven shaft gear comprising a gear set which is determinative of the drive shaft to propeller shaft gear ratio, said gear set being replaceable to provide a different drive shaft to propeller shaft gear ratio if so desired.

6. In an outboard motor having an engine and a lower unit and a drive shaft housing connecting the engine and lower unit, said lower unit having a propeller shaft housing and a gear case spaced above said propeller shaft housing, a generally horizontal propeller shaft rotatably disposed in the propeller shaft housing and projecting therefrom to carry a propeller, a generally vertical drive shaft rotatably disposed in said drive shaft housing and drivingly connected to the engine and extending downwardly into the gear case, a plurality of generally vertical driven shafts extending between the gear case and the propeller shaft housing, a bevel gear means in said propeller shaft housing and comprising a bevel pinion gear carried on each of said driven shafts and a corresponding bevel gear carried on said propeller shaft in meshing engagement with the respective pinion gears to provide for rotation of a propeller, said bevel gears on said propeller shaft being adapted for reverse assembly with respect to the bevel pinion gears to provide for counterrotation of the propeller shaft to drive a propeller having pitch of opposite hand, and reversing gear means in said gear case for drivingly connecting the drive shaft to the driven shafts to provide for propeller rotation selectively in the forward and reverse directions.

7. In an outboard motor having an engine and a lower unit and a drive shaft housing connecting the engine and lower unit, said lower unit having a propeller shaft housing and a gear case spaced above said propeller shaft housing, a generally horizontal propeller shaft rotatably disposed in the propeller shaft housing and projecting therefrom to carry a propeller, a generally vertical drive shaft rotatably disposed in said drive shaft housing and drivingly connected to the engine and extending downwardly into the gear case, a plurality of generally vertical driven shafts extending between the gear'case and the propeller shaft housing, bevel gear means in said propeller shaft housing and drivingly connecting the driven shafts to the propeller shaft, and reversing gear means in said gear case for drivingly connecting the drive shaft to the driven shafts to provide for propeller rotation selectively in the forward and reverse directions including a forward drive gear and said forward drive gear is meshingly engaged with a gear carried on one of said driven shafts, said forward drive gear and said driven shaft gear comprising a gear set which is determinative of the drive shaft to propeller shaft gear ratio, said gear set being replaceable to provide a different drive shaft to propeller shaft gear ratio if so desired.

8. The invention as set forth in claim 7 wherein the upper portion of the lower unit comprises a separable member serving as a gear case cover, upon removal of the lower unit from the drive shaft housing said cover member being removable from the lower unit to expose the replaceable gear set.

References Cited UNITED STATES PATENTS 3,148,557 9/1964 Shimanckas l15l8 XR 3,154,047 10/1964 Casale 115-34 3,350,879 11/1967 Boda et al 11517 XR ANDREW H FARRELL, Primary Examiner US. Cl. X.R. 11534 

